Fuel delivery valve and injection apparatus employing same



March 14, 1967 R. J. MADDALOZZO 3,309,024

FUEL DELIVERY VALVE AND INJECTION APPARATUS EMPLOYING SAME Filed Jan. '7, 1965 3 Sheets-Sheet 1 IN VEN TOR RAYMOND J. MADDALOZZO BY (J W ATT'Y March 14, 1967 R. J. MADDALOZZO 3,309,024

FUEL DELIVERY VALVE AND INJECTION APPARATUS EMPLOYING SAME Filed Jan. 7, 1965 3 Sheets-Sheet 2 Sw n K PT

HIIIIII W INVENTOR RAYMOND J. MADDALOZZO March 14, 1967 J. MADDALOZZO 3,309,024 FUEL DELIVERY VALVE AND INJECTION APPARATUS EMPLOYING SAME Filed Jan. 7, 1965 3 Sheets-$heet 5 IN VENTOF? RAYMOND J. MA DDA LOZZO United States Patent C) 3,309,024 FUEL DELIVERY VALVE AND INJECTION APPARATUS EMPLOYING SAME Raymond J. lwaddalozzo, Chicago, Ill., assignor to International Harvester Company, Chicago, 111., a corporation of Delaware Filed Jan. 7, 1965, Ser. No. 423,916 8 Claims. (Cl. 239-) This application is a continuation-in-part of copending Maddalozzo U.S. patent application Ser. No. 411,999 filed Nov. 18, 1964, and my description of the fuel pump delivery line structure and of other common matter disclosed therein is incorporated herein by reference.

The present invention relates to engine fuel injection apparatus. It more particularly relates to an improved form of the basic spring loaded retraction valve or delivery valve employed in such apparatus. The basic valve is included in an upstream position in a fuel delivery line leading to the injection nozzle valve or nozzle plunger provided on an engine cylinder, and functions to maintain valves after each injection takes place.

According to practice in the past, the fuel delivery line in a diesel engine handles the controlled intermittent flow of liquid fuel one way between the working chamber of a charging pump and a combustion chamber or the like. It is therefore the practice to have the delivery valve in the line function as a check valve in the output of the pump working chamberso as to prevent flow reversal. The lack of bidirectional flow gives rise to a serious difficulty in the event of a plugged nozzle in an engine cylinder, and the check valve operation of the delivery valve allows the delivery line to be pumped up to unrelieved pressures of an unwanted high value. Permanent dam. age can result due, among other things, to swelling and unbalanced hydrostatic loading in the distributor of the injection pump.

My invention, in accordance with a preferred emb0dimerit thereof, materially reduces or substantialy eliminates the foregoing difiiculty. Moreover in one modification of the invention, fluid under a transient excessive pressure from another cause, is released by being sequestered in the delivery line for employment on the next pumping stroke, without being allowed to recirculate to the fuel tank and thereafter to be re-introduced by the pump into the flow passage to the delivery line, all as will now be explained. Also, certain features, objects, and advantages will either be specifically pointed out or be come apparent when, for a better understanding of the invention, reference is made to the following written description taken in conjunction with the accompanying drawings, which show certain preferred embodiments thereof and in which:

FIGURE 1 is a longitudinal sectional view of a port metering, opposed plunger, rotary distributor, diesel fuel injection pump embodying the present invention;

FIGURES 2 and 3 are fragmentary enlargement views of the retraction valve appearing in the longitudinal fuel passage of FIGURE 1, the valve being shown with the parts in sequential operating positions;

FIGURE 4 is a longitudinal sectional view of the valve being disassembled in a fixture; and

FIGURES 5, 6, 7 and 8 are longitudinal sectional views of a modification of the valve shown in sequence of operating positions.

More particularly in FIGURE 1 of the drawings, a housing or casing 10 of the present device is shown having three bolted together sections consisting of a pump 12 at one end, a primary pump housing 14 at the opposite end, and a so-called distributor head housing 16 assembled between the end sections or housings. An engine connected pump shaft 18 extends longitudinally through the device and is journalled for rotation in spaced apart roller type and sleeve type bearings 20 and 22, respectively, fixed in the pump housing 12 and in the distributor head housing 16. The particular fuel injection device illustrated is intended for a six cylinder, four stroke cycle, solid injection diesel engine, in which case the pump shaft 18 is driven in time to the engine and at a speed proportionate to crank shaft speed, specifically, at one half of the crank shaft speed.

The shaft 18 is the heart of the mechanism of several operating components within the housing 10, all contributing in properly timed relation to supply metered amounts of fuel to the individual nozzles 23 which communicate with combustion chambers in the six engine cylinders, not shown. The power input to the pump is the torque applied to a gear 24 fast to the shaft 18, the gear being connected to the engine.

The pump shaft 18 has a longitudinally drilled passage 25 which is intersected at one end by first transverse passages terminating in metering ports 26, and by second transverse passages terminating in timing ports 28, there being two metering ports and two timing ports.

A centrally located charging pump component within the so-called distributor head housing 16 is shown having a transversely disposed, cylindrically shaped pump chamber 30 formed in the shaft 18 and communicating with the passage 25 approximately midway between its ends.

A distributor component comprises a retraction or delivery valve 32 connected in the longitudinal passage 25 so as to unseat or open in a direction away from the pump component, a set of suction ports 34 which intersect the passage 25 on the pump side of the valve 32 and which periodically communicate with an annular chamber 36 which holds the so-called transfer fuel in the housing 16, a distributor port 38 which communicates with the passage 25 on the opposite side of the valve 32 and which, during two revolutions of the engine crank shaft, registers at uniformly spaced apart intervals with each of six housin-g passages 40, and a set of fuel delivery lines 42 leading from the six housing passages to the nozzles 23. Socalled banjo fittings 44 connect the lines liquid tight to the distributor head housing 16, being secured to the latter by individual hollow connecting screws 46.

A dual sleeve component which establishes the time of actuation of the retraction valve 32 includes a timing sleeve 48 which rotatably receives the pump shaft 18, a governor sleeve 50 which rotatably receives the shaft 18 at a point between a governor component 52 and the timing sleeve 48, and an alignment pin 54 connected between the sleeves 48 and 50 and holding them so as to be nonrotatable but relatively axially movable to one another. The timing sleeve 48 has a connection, not shown, to a pivoted arm termed a governor spring arm 56.

Six straight cut slots 58 in the bore of the timing sleeve 48 are parallel to the pump shaft axis and cooperate with the timing ports 28 to spill fuel therefrom during short, equally spaced apart intervals. Six helically cut slots 60 in the bore of the governor sleeve 50 cooperate with the metering ports 26 to allow fuel to escape therefrom during short, equally spaced apart intervals in the cycles. The

straight timing sleeve slots 58 keep the beginning of de-v livery constant whereas the helically cut slots 60, when the governor sleeve 50 is adjusted by the governor component 52,,vary the end of fuel delivery.

The charging pump component referred to provides the pressure for, opening the retraction valve 32,.and comprises the transverse, cylindrical chamber 30, a pair ,of

rotary and reciprocatory plungers 62 slidablyreceivedin the opposite outer ends of the chamber 30, a cam ring 64 .fixed in the housing 16 in the plane of the plungers 62, a pair of rotary and reciprocatory cam followers or rollers 66 which ride along a set of six inwardlyprotruding cams on the. ring 64, and an interposed tappet .68 connecting each roller 66-to a differentone of the plung-- ers 62 causing the plungers to periodically compress and thenrelease an interposed return spring 70 upon rea spective pumping and suction strokes.

Further-components in the device, indicatedby general 1 of the primary pump 78, a transfer outlet port 86 which communicates with the pressure side of the pump :78, a transfer conduit 88 leading from the outlet port 86 and including therein a final filter90ythe annular chamber 36,. a communicating charging passage 92 in the housing 16 which is connected during shaft rotation to the suction ports 34 in periodically timed relation, a set of.

diagonal intake passages 94 formed in the shaft 18,2an'd thence into the pump chamber 30.

On the discharge stroke of the pump plungers, the fuel follows a sequence flowing in different directions through, a three-way split path. During predetermined,

initial collapsing movement of the plungers 62, toward one another, fuel escapes from the shaft 18 into the pump housing 12' through the registering straight slots 58 until the spill is cut off by the sleeve 48 covering the timing ports 28. During further collapsing movement of the plungers 62, fuel pressure increases so as to open the retraction valve 32, and fuel is forced through the registering one of the fuel nozzle delivery lines 42. During,

final, radially inward collapsing movement of the plungers 62, two of the helical slots 60 register with the two metering ports 26 so as to spill the balance of the pumped fluid into the pump housing 12.

A drain conduit 96 returns a portion of the spilled fuel from the pump housing 12 to the fuel tank 80. A

.spring loaded recirculation valve, not shown, connected between the housing 12 and the suction side of the primary pump component 78 returns another portion ofthe spilled fuel. Finally, a pressure regulating valve 98 connected between the annular chamber 36 and the suc-i tion side of the primary pump component 78 unseats and returns fuel to the latter whenever pressure becomes ex-. cessive on'the pressure side of the pump component 78.

The injector on an engine cylinder is supplied with fuel. toward the end point of each compression stroke. When the injector on the cylinder sticks down, at that point at each successivecompression stroke a meteredquantity of fuel is pumped into the fuel delivery line, and is. trapped thereby closure of the retraction valve attend.

ant with opening of the spill ports in the fuel pump. The pressure build-up (8,000 to 10,000 p.s.i.) internally expands the pump shaft on the downstream side thereof,

closing the clearance between the shaft and sleeve type bearing bore as well as forcing the shaft toone side in the bearing. In some, instances the lubrication film breaks down, causing pump failure due to shaft seizure. This difficulty is avoided in the'embodiment of my invention next described.

In'the embodiment of the retraction valve 32a illustrated in FIGURES 2, 3 and 4, the assembly includes a main or primary valve 100 having'a generally cylindrical .shape and a secondary ball valve'102 therein.- The primary ,valve 100-fits within a guiding bore104' forming an enlargement of the general longitudinal passage 25 within the shaft 18. A lengthwise extending passage 106 within the valve 100 communicates at one. end through the vpassage .25, with the fluid inside the.

pump chamber 30,not shown. The valve 32a controls the flow passage leading from. the pump chamber and including a portion of the passage 25,, the distributing port 38,.not shown, the individual housing passage 40, and the fuel delivery lines 42, not shown. The fluid transferred through the ball "valve 102 escapes from the flow passage and is returned similarly to the spilled fluid of thecharging pumpso as to enter the suction side of either the charging pump or primary pump,

The mechanism of the ball valve 102 is self-contained within the primary valve 100,.and includes a helical c0m.

pressingspring 108, and ,a backing pad 110 which is between one end of the spring 108 and the ball 102 at that end and ,which cooperates therewith to keep the ball biased against a conical seat .112 formed in the passage 106. At the opposite end the spring 108' thrusts againstthe flat end of a spring seat 114. The seat 114 traps a circular snap =ring116 between the bevelled end 118 of the, seat'and anvinsidei annular groove 120 that is providedin an end of the valve chamber which is formed by the lengthwise extending passage 106;; The

diameter of the seat 114 decreases: in the axially outward direction due to the bevel.

Theseat 112 for the ball valve 102 is offset downstream from .a set of side ports 122i extending radially through the wall of the primary valve 100. The valve has a reduced end portion 124 defining a one-way flow passage, 126 and complementing the body'of the, valve 100 topresent a spring seat shoulder 128. A primary valve I spring 130 has a fixed end engaginga combined valve stop and plug 132, and a free end engagingtheseat shoulder 128 for urging the primary valve 100 to'move toward the pump=into the closed position illustrated in FIGURE 3.

Although the retractiondistanceillustrated at R between the edges of the ports 122 and covering shoulder 134 at the end of the guiding bore 104 is shown with exaggeration was to be perceptible at all, in an actual physical embodiment of the invention the primary valve 100 was a zero retraction valve. In other words, in the valve closed positionthe edges of the ports 122 were at or just barely past the plane of the shoulder 134. Increase in the delivery line volumefollowing cut-off was not only unnecessary but undesirbale, because the nozzles 23, not shown, were cam driven, mechanical injectors in which mechanical force rather than injection pump pressure caused injection (20,000 p.s.i.) to occur. Hence there was no possibility of secondary injection and reducing the delivery line pressure any further would have 1 been wasted effort.

If the location of the'ports 122 is'charged, the valve 32a can berused with injection apparatus of a different type. That is to say,; the ports 122 can be relocated by positioning them more tothe left than is shown'in FIG- URE 3, in which case the retraction distance R can have a finite value such as several millimeters. In that case the ,valve 32a is readily adaptable for use with the so called open or check valve type of injector nozzles, or the closed type nozzles in which injection is controlled by a spring biased valve between the pump and injection nozzle spray orifices .and which are actuated to the open position by the fuel pressure.

The zero retraction valve just referred to, from an initial injector-filling, open position illustrated in FIG- URE 2, affords a novel method of controlling the flow of fluid. The respective steps of such method comprise inducing a pressure drop in the delivery line while cutting off communication between the pump chamber and the line, which drop will normally result in approximately a predetermined residual pressure after each injection, and immediately thereafter, in reacting as illustrated in FIG- URE 3 to each plugged nozzle situation, affording through the one way passage 126 and into the pump chamber an unlimited escape, from the line, of excess fluid down to a pressure higher than said predetermined pressure but preferably only slightly higher. For use with the cam driven, mechanical injectors referred to, the ball valve 102 unseats in the direction of the pump chamber, and the pressure in one instance was at or above 1600 psi.

Obviously, if the fuel flow were maintained undiminished through the ports 122 as the primary valve 100 shifts into fully closed position, the portion of the volume of the delivery line vacated by the valve would be taken up by a like volume of incoming fuel. But an inherency of the valve 109 is not to maintain unrestricted flow, and the valve actually induces a pressure drop in the line while progressively cutting off communication between the chamber 30 and the fuel delivery line. It does so because it is physically enlarging the line while moving toward cut off. The pressure drop thus induced is more at the higher running speeds than at low load, low speeds for reasons which, at least in theory are explained hereinafter, and hence the predetermined residual pressure in the line is higher at the low load, low speeds.

In case the valve ports 122 are drilled at points giving the retraction distance R some finite value, for use with closed type or open type injection nozzle valves for example, the flow is controlled thereby in steps comprising: inducing a pressure drop in the delivery line while cutting oh? communication between a pump chamber and the line; enlarging the internal volume of said line a predetermined fixed amount, after cutting ofi" communication between the line and chamber, under substantially all normal operating conditions so that a further drop occurs normally resulting in approximately a predetermined residual pressure; and immediately thereafter, in each plugged nozzle situation, affording unlimited escape from the line of excess fuel down to a pressure higher than the predetermined pressure, the latter pressure being at least a major fractional proportion of the regular nozzle injection pressure. In this situation, the predetermined residual pressure which is sought when the nozzles operate normally is a major fractional proportion of the normal nozzle injection pressure.

In FIGURE 4, the valve 32a during assembly and disassembly is placed with its reduced end 124 downwardly and is received in the socketed fixture 135 of an arbor press 136. An adapter 138 is inserted and pressed downwardly, forcing the seat 114 inwardly away from the groove 120. During disassembly, radial tool admitting holes 140 in the valve 100 receive a tool 142, the holes intersecting the groove 120 and allowing the tool 142 to spring loose the snap ring 116 into its withdrawn position indicated by the broken lines 116a. The snap ring is a mutilated spring wire ring, of which the opposite ends are deliberately spaced apart by angular spacing a which in one instance was 60. In this way, suflicient clearance is provided for the spring ring to circumferentially collapse, both for disassembly and for assembly of the valve 32a.

Complete disassembly comprises the foregoing steps, followed by opening the arbor press 136, withdrawing and inverting the valve 100, and axially outwardly removing the subassembly therein including the ball valve 102. The embodiment of my valve next described relieves the line from the transient, rebounding pressure waves resulting from injection cut ofi? in open type and closed type injection nozzles.

In the embodiment of FIGURES 5, 6, 7 and 8, the primary valve 144 shown has a reduced end 146 at the right as viewed in the figures, and at the opposite end carries an auxiliary end part 148 threaded thereto and defining therewith an internal, through cavity 150 in the valve. A secondary ball valve 152 which opens toward the pump chamber is seated on a bevelled seat 154. Another secondary ball valve 156 is received in a close fitting cylindrical bore 157, and unseats away from the pump chamber and from its semi-spherical seat 158. A one-way fiow passage 160 is within the auxiliary part 148 and a coaxial one way flow passage 162 is in the reduced end 146 of the primary valve.

A common helical spring 164 biases bot-h valves .156 and 152 upon their seats, the spring being a compressing spring and having an interposed backing pad 166 at one end engaging the ball 156 at that end and having another interposed backing pad 168 at the opposite end engaging the ball 152 at that end. A pair of confronting stops 170 connected to the respective backing pads 166 and 168 limits opening movement of the ball valve 156. Another helical spring 172 acts to seat only the ball valve 152, the spring thrusting at one end against the end part 148 and thrusting at the opposite end against'the backing pad 168. The primary valve 144 has a closing spring 174 which thrusts at one end against a plug 176 and which thrusts at the other end against a shoulder on the valve adjacent the reduced end 146 thereof.

The valve 321) includes one-way primary ports 1'78. FIGURE 5 shows the valve with the ports 178 in closed position, but the showing is exaggerated so that the retraction distance R of the ports past a cut off edge or shoulder 180 is perceptible. Actually in practice the primary valve 144 has zero retraction, i.e., when the valve 144 halts, the edge of the primary passages 178 registers with or is just barely past the shoulder 180 so that the valve 144 does not enlarge the delivery line volume after cutting off injection flow of fuel.

The retraction valve 32b of FIGURE 5 retains the full closed position illustrated, during the suction phase of a pumping cycle and during both spill phases of the pumping cycle.

Beginning with a fully open, injection phase illustrated in FIGURE 6, the valve 32b controls the flow in three steps. The predominant closing spring 174 is the first to act as injection terminates. Such spring action on the valve 144 causes the one-way ports 178 to move past the shoulder 180, progressively restricting the flow passage from the valve cavity 150 to the delivery line while enlarging the internal volume of the delivery line. Because of a drop in the pressure due to the valve, the pressure decreases to an initial residual pressure in the line at the point of cutting off of communication.

The latter point is illustrated in FIGURE 7, following which the spring action of the expanding spring 164 forces the ball valve 156 into and through the closely fitting bore 157. This retraction motion reduces the pressure to a low pressure in the cavity 150 by enlarging the internal volume of the cavity and leaving a void therein. The valve 156 then comes to rest on its seat 158.

The ball 156 is readily provided on a select-fit basis for reception within the bore 157, and can be economically supplied because highly accurate, graded metal balls are cheap and in plentiful supply. This feature of my valve gives it a decided cost advantage over volume displacement valves of the cylindrical retraction type and top sealing retraction type, both of which are in common use for fuel delivery line work. The valve 156 is in effect closed when it first contacts the downstream end of the bore 157, and the continued upstream movement thereof until it settles on the seat 158 is pure movement directly enlarging the volume of the cavity-150.

7 With the valve 156 seated as illustrated in FIGURES, the parallel springs 164 and 172 thereafter accommodate by yielding with opening movement of the ball valve 152, controllably releasing the rebounding pressure wave from the delivery line by allowing it to spill into, and. the delivery linetransient pressure to dissipate itself to a safe operating level in, the low pressure of the voidcontaining cavity 150.

The opening-value for nozzle valves varies, being of theorder of 750 p.s.i. for a precup engine, and of the order of 2300 to 3000 p.s.i. for direct injection nozzle. In the instance of a direct injection nozzle requiring an opening pressure of 2300 p.s.i., the force of the spring 174 would be something less than 2300 p.s.i., e.g., 2100 p.s.i., The combined forceof the parallel. acting. springs 164 and 172 is such that they allow the ball valve152 to openat a major fractional proportion of the nozzle opening pressure, e.g., 1600 psi. which in the above instance would amount to 70% of nozzle opening pressure;

The more general range for opening is 1600-2800 p.s.i.

A stop 182 on the plug 176 limits the opening travel of the primary valve 144 by engaging the reduced end 146.

It is apparent in FIGURE 5 that the internal volume of the fuel delivery line can be further increased by offsetting the one-way primary ports 178 so that the. retraction distance R hasa finite value such as several rnillirneters. In any case,.when idling or at the lower speeds of the engine, the rebounding pressure wave resulting from closure of the injection nozzle valve is rela- 'tively mild. Therefore, the pressure pulsations in the line are small. and littleor no fuel is admitted by unseating the valve 152 and entering'the cavity 150.

At the higher speeds, particularly during full load operationsv when large quantities of fuel are being pumped, the rebounding pressure wave from the closing nozzle valve is comparatively great or severe. This wave not only tends to accelerate closure of the primary valve 144 of FIGURE 6, but has two further noticeable effects. Less importantly, it causes thevalve 144 to, close so fast that inadequate fuel escapes through the ports 178 within the shortened time period to properly replenish the de-. livery line volume being vacated by the closing valve 144. The wave strikes the ball valve 152 with a peak pressure causing the valve to unseat and to spill a sub= stantial quantity of fuel into the cavity 150s However, the fuel so transferred is not bypassed to the input side of the charging; pump or the primary pump, butmerely trapped right withinthe delivery valve 32b for immediate re-entry into the delivery line at the start of the next injection stroke of the charging pump plungers.

From the foregoing it is seen that the valve 32a in accordancewith FIGURES 2 and 3 provides a novel action preventing damage when an injectornozzle plugs, r and allowing an engine to operate on all cylinderswhich remain active, with no harm to the injector pump. The retraction valve 32b in accordance with FIGURES 5, 6,

7 and 8 provides a novel action preventing damage frompressure fluctuations and also obviating secondary injection or nozzle dribble clue to such fluctuations.

As hereindisclosed, the invention is shown applied to the nozzles for a six cylinder engine. It is evident that it applies equally well to four cylinder and eight cylinder engines.

So also the'bidirectional pressure relief type, delivery valves herein are shown to embody cylindrical type primary valves, but self-evidently, my invention can be appliedto the poppet or so called top seating type delivery valves;

What is claimed is:

1. In a fuel injection system subject to a rebounding pressure wave following injection, and including nozzle means to deliver the output and a pump chamber to sup ply the input. of fuel thereto, and together having an interconnecting cavity with opening means therein, the method of C tIQJJ g P I-iHjeCIiQn fuel flow beginning drawing a void in said cavity by enlarging the internal. volume thereofat the location of one closed open-,

ing means, while maintaining, at constant volume,

the fuel which is immediately availableasinput to the nozzle means and which is inthe path'of the rebound wave; and

at least partially refilling the void by temporarily opening one opening means and controllably communicating thereinto the peak pressure of said rebounding wave so as to dissipate same to the maximum operating level desired.

2. In a fuel injection system, the method of controlling the flow of fluid in a delivery valve through-cavity and in a delivery line, connectedin series betweenthe pump chamber'of a pump and an injection nozzle following each injection of fuel, :which comprises:

progressively restricting the flow passage from said chamber and cavity to thedelivery line while enlarging the internalvvolumeofthe delivery line, so

thatthe pressure dropwill result in approximately a predetermined residual pressure in said line after eachinjection of fuel at the time of the cutting off of communication from said, chamber and cavity to the delivery line;

reducing the pressure to a low pressure in said cavity 7 by enlarging the internal volume of said cavity; and thereafter controllably releasing, the rebounding pressure wave from the delivery line by directing it to spill into, and the delivery line transient pressure to dissipate .itself to a safe operating level in, the low bore while concurrently enlarging the internal volume of the line, said primary valve having a concentric fiow cavity therein presenting separate valve seats at opposite ends; one coaxial secondary valve within, and onthe valve seat at one end of,ithe flow cavity in the primary valve, said secondary valveunseating; in the direc-' tion away from the pump chamber or retracting in the direction thereof as to enlarge the internal volume'of the How cavity; and one coaxial secondary valve within, and on the valve seat at the opposite endof, the flow cavity in the primary valve, and unseating inthe direction of the.

pump chamber. 4. The invention of claim 3, including spring means to bias a plurality of said valves toward-the closed position, including a common seating. spring mechanically interconnecting the secondary valves.

5. The invention of claim 4, thefirst-namedsecondary valve of the invention being at the end of the flowvcavity adjacent thejpump chamber and the second-named'secondary valve being at a remote end of the cavity, and each opening in thedirection of the other;

6. The invention of claim 3, the primary valve consisting of a cylinder type delivery valve and the secondary valves consisting of ball valves.

7.,The invention of claim 5, including two spaced apart, confronting stop members which back the respective secondary valves. and which engage to limit relative 9 l0 movement between the secondary valves during opening 2,040,846 5/1936 Hesselman 239-584X of at least one of the valves. 2,090,781 8/1937 Camner 137-4939 X 8. The invention of claim 7, characterized wherein 2,602,702 7/ 1952 Kovach 23989 X said common seating spring surrounds the stop members. 2,696,828 12/ 1954 Husing 137-4939 X 5 2,805,679 9/1957 Schrameck 137493.6 X

References Cited by the Examiner M. JR., Primary Examiner.

1,999,967 4/1935 Miller et a1 137- 493.3 WILKS, Assistant Examiner- UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,309,024 March 14, 1967 Raymond J. Maddalozzo It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 21, after "maintain insert a desired residual pressure between the retraction and nozzle Signed and sealed this 21st day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

1. IN A FUEL INJECTION SYSTEM SUBJECT TO REBOUNDNG PRESSURE WAVE FOLLOWING INJECTION, AND INCLUDING NOZZLE MEANS TO DELIVER THE OUTPUT AND A PUMP CHAMER TO SUPPLY THE INPUT OF FUEL THERETO, AND TOGETHER HAVING AN INTERCONNECTING CAVITY WITH OPENING MEANS THEREIN, THE METHOD OF CONTROLLING POST-INJECTION FUEL FLOW BEGINNING WHEN AT LEAST ONE BUT NOT ALL OPENING MEANS ARE OPEN COMPRISING: CLOSING THE OPEN OPENING MEANS IN SAID CAVITY; DRAWING A VOID IN SAID CAVITY BY ENLARGING THE INTERNAL VOLUME THEREOF AT THE LOCATION OF ONE CLOSED OPENING MEANS, WHILE MAINTAINING, AT CONSTANT VOLUME, THE FUEL WHICH IS IMMEDIATELY AVAILABLE AS INPUT TO THE NOZZLE MEANS AND WHICH IS IN THE PATH OF THE REBOUND WAVE; AND AT LEAST PARTIALLY REFILLING THE VOID BY TEMPORARILY OPENING ONE OPENING MEANS AND CONTROLLABLY COMMUNICATING THEREINTO THE PEAK PRESSURE OF SAID REBOUNDING WAVE SO AS TO DISSIPATE SAME TO THE MAXIMUM OPERATING LEVEL DESIRED.
 3. A FLUID INJECTION SYSTEM INCLUDING AN INJECTION NOZZLE FOR FUELING AN INTERNAL COMBUSTION ENGINE SAID SYSTEM FURTHER INCLUDING: PUMPING MEANS WITH A PUMP CHAMBER FOR SUPPLYLING FLUID TO THE INJECTION NOZZLE; MEANS FORMING A FLUID DELIVERY LINE INTERCONNECTING THE PUMP CHAMBER AND THE NOZZLE; AND AN ASSEMBLY OF PRIMARY AND SECONDARY VALVES CONNECTED IN THE FLUID LINE, THE PRIMARY VALVE HAVING GUIDING BORE MEANS THEREFOR IN THE LINE WHEREIN THE VALVE IS GUIDED TO OPEN THE BORE AND TO SHUT OFF THE BORE WHILE CURRENTLY ENLARGING THE INTERNAL VOLUME OF THE LINE, SAID PRIMARY VALVE HAVING A CONCENTRIC FLOW CAVITY THEREIN PRESENTING SEPARATE VALVE SEATS AT OPPOSITE ENDS; ONE COAXIAL SECONDARY VALVE WITHIN, AND ON THE VALVE SEAT AT ONE END OF, THE FLOW CAVITY IN THE PRIMARY VALVE, SAID SECONDARY VALVE UNSEATING IN THE DIRECTTION AWAY FROM THE PUMP CHAMBER OR RETRACTING IN THE DIRECTION THEREOF AS TO ENLARGE THE INTERNAL VOLUME OF THE FLOW CAVITY; AND ONE COAXIAL SECONDARY VALVE WITHIN, AND ON THE VALVE SEAT AT THE OPPOSITE END OF, THE FLOW CAVITY IN THE PRIMARY VALVE, AND UNSEATING IN THE DIRECTION OF THE PUMP CHAMBER. 